Diarrhea in Dogs & Cats: Causes, Treatment & Prevention

Diarrhea in Dogs & Cats: Causes, Treatment & Prevention

Diarrhea is unpleasant. Period. It's no picnic for your pets either. It’s almost worse because they depend on you to let them out quickly when they really need to go.

Inconvenience and unpleasantries aside, diarrhea can be a dangerous condition.

What is diarrhea?

Diarrhea is the passing of large quantities of liquid or loose stool. It’s typically the result of inflammation in the digestive system. When your pet has diarrhea, he’s unable to absorb water and nutrients, which can lead to dehydration and malnutrition.

What causes diarrhea in dogs & cats?

Diarrhea is often a symptom of a separate condition. There are several things that can cause your pet to have diarrhea, such as:

  • Food
  • Infection
  • Toxins
  • Medication
  • Autoimmune reaction

Why does my dog have diarrhea?

Whether it’s a general food intolerance or he just got into the garbage when you weren’t looking, oftentimes diarrhea is simply the result of something your pet ate. 

Diarrhea can also occur when you switch to a new type of food too quickly. If you’re planning to switch up his diet, be sure to do it gradually to avoid an upset tummy. Start by replacing 25% of his current food with the new food for a couple of days. Then repeat the process, replacing 25% more every other day until he is eating 100% new food.

Toxic plants such as tulips and lilies can cause diarrhea. Try to keep your pets away from them when you’re out on your walks.

Other toxins, like chocolate, xylitol, pesticides and antifreeze can also cause diarrhea when ingested. Keep dangerous stuff up and out of reach from pets.

Allergies, stress and hyperthyroidism are all contributing factors to diarrhea, as are anti-inflammatories and antibiotics

How can I tell what caused my pet’s diarrhea?

The appearance of your pet’s stool may help you determine the cause of his diarrhea.

If you see foreign objects (or what’s left of them) in your pet’s stool, that’s often the most obvious answer to what’s causing his diarrhea. 

If there is blood, which may appear as red, black or tarry streaks, in your pet’s stool, call your vet immediately. Bloody stool might indicate digestive tract bleeding.

If your pet is unsuccessfully straining to evacuate his bowels frequently (every 10-15 minutes or so), it might indicate inflammation of the large intestine

On the flip side, if he’s going less frequently but you’re seeing significantly more bulk than usual, it may indicate inflammation in the small intestine and/or the inability to digest food.

Stool that’s thin and runny could be a sign that food isn’t being absorbed properly in the small intestine. That can happen for any number of reasons, including food intolerances or allergies causing inflammation. It could also be a sign of inflammatory bowel disease (IBD), a parasitic infection like giardia, or a bacterial infection.

Mucus in your pet’s stool may be a sign of colitis. Have your vet check it out right away.

Intestinal worms (they look like white spots in the stool) can also cause diarrhea. If your pet consumes contaminated water or feces, he can pick up internal parasites like tapeworms and roundworms. Your vet can help you choose the right treatment plan for internal parasites.

Additional symptoms to watch out for

If your pet’s diarrhea is accompanied by other symptoms, there might be something more dangerous happening. Call your vet right away if you see any of the following signs:

  • Lethargy
  • Vomiting
  • Discoloured gums
  • Blood, worms or mucus in the stool

Diagnosing the underlying cause of diarrhea

Collect a stool sample 4 - 6 hours before your vet appointment. After reviewing it under a microscope, your vet will consider the colour, shape, frequency and contents of the stool, looking for intestinal worms or unusual objects your pet may have ingested.

Sometimes, there is no clear answer to why your pet has diarrhea. The important thing is to treat it so he doesn’t become malnourished and dehydrated.

How to treat your pet’s diarrhea

Your pet's digestive system will need to rest after having diarrhea. Unless your vet advises you to withhold food for 24 hours, feed him a bland diet of boiled, skinless, unseasoned chicken paired with some white rice, until his digestion starts to normalize. When you reintroduce your pet’s regular food, do it slowly so as not to upset his tummy again.

Specific treatments depend on the underlying cause of the diarrhea. 

If intestinal worms are the issue, your vet may prescribe a deworming medication.

If your pet ate something toxic, your vet may treat with IV fluids or medication, depending on the substance consumed. Fomepizole, for example, is used to treat antifreeze toxicity.

Diarrhea often clears up on its own. A digestive supplement may help to speed your pet’s recovery.

How can I prevent my pet from getting diarrhea?

It happens.

You might not be able to prevent it entirely, but there are a few things you can do that might help ...

  • Avoid foods that cause digestive inflammation
  • Keep toxic materials up and out of reach
  • Avoid changing your pet’s food too quickly
  • Add a digestive supplement to keep his gut healthy

Above all else, keep a close eye on your fur-baby when he gets diarrhea. If it lasts longer than 24 hours, call your vet. You don't want your pet to become dehydrated or malnourished. And you certainly don't want to overlook a potentially dangerous underlying condition.